var yellow1 = Symbol.for("Yellow");
var yellow2 = Symbol("Yellow");

console.log ( Symbol.keyFor(yellow1) );    // "Yellow"

console.log ( Symbol.keyFor(yellow2) );    // "Yellow"

console.log('-----------------------\n')



let hd = Symbol.for("后盾人");
console.log(Symbol.keyFor(hd)); //后盾人

let edu = Symbol("后盾人");
console.log(hd == edu) // false 
console.log(Symbol.keyFor(edu)); //undefined



console.log(hd, edu)
console.log(hd.description, edu.description)
